Question

Draw and explain filled system thermometer.

Answer 1

A filled system thermometer is a type of thermometer that uses a liquid or gas that expands and contracts based on temperature changes to measure temperature. These thermometers work on the principle that a substance (usually a liquid like mercury or alcohol or a gas) changes its volume when the temperature changes.

Here’s a simple explanation and drawing for a filled system thermometer:

Components:

1. Thermometric Fluid: This is the substance inside the thermometer, such as mercury or colored alcohol, which expands or contracts with temperature changes.
   

1. Glass Tube: The fluid is enclosed in a sealed glass tube.
   

1. Bulb: The bulb at the bottom of the thermometer holds the thermometric fluid. The bulb is often larger to store more of the fluid.
   

1. Scale: There is a scale (Celsius or Fahrenheit) marked on the thermometer for easy reading.
   

Working Principle:

1. As the temperature increases, the thermometric fluid inside the bulb expands and moves up the capillary tube.
   

1. When the temperature decreases, the fluid contracts and moves down.
   

1. The height of the fluid column in the capillary tube corresponds to the temperature.
   

Example: Mercury Thermometer

1. Mercury expands when heated and rises up the narrow capillary tube.
   

1. The thermometer is calibrated with a scale, so by reading the level of the mercury, you can determine the temperature.
   

Drawing:

Here’s a simple illustration of a filled system thermometer:

`
   _______________________
  |                       |
  |    Glass Tube          |
  |                       |
  |      |                |
  |      |                |  
  |     | |               |
  |     | |   (Thermometric Fluid)  
  |     | |__________     |
  |        |             |
  |   Bulb |             |        
  |______|______________|         
`

Explanation of the Parts:

1. Bulb (Bottom part): Holds the thermometric fluid.
   

1. Capillary Tube: A narrow, thin tube that connects the bulb to the scale. The fluid moves up and down in this tube.
   

1. Scale: The numbers on the side of the tube are used to measure the temperature based on the fluid level.
   

In summary, the filled system thermometer works by using a fluid that expands or contracts in response to temperature changes, with the height of the fluid providing an accurate temperature reading.